While I'm not sure if anyone has gone to the trouble of writing a guide per se, I can give a couple of pointers.
Number of Attendees:
THIS is wide open - and often depends on the availability of those you're inviting for that certain day. After having a few though, you'll come to appreciate the smaller ones, simply because they allow a bit more interaction with each and every member. The smallest I attended had 5 attendees - the largest, just over 30. With the small one, we were all at the same table, which allowed for plenty of discussion. The largest simply did not allow the ability to meet and discuss much with everyone.
Food cost/Corkage fees:
As we all come from different walks of life, not all of us have the disposable income for an expensive dining experience - all I can suggest here is for you to feel out the group, or perhaps even ask what price point everyone is comfortable with. Up here, I can't remember the last time we spent more than $80 per person, including food, taxes, corkage and tip. You'll find that the friendlier the price point, the more winos will show up! As to corkage, it fluctuates from restaurant to restaurant. Again, up here it's been as low as $10, or...I've seen restaurants advertise up to $50. Depending on the night of the week you decide to meet, restaurants may forego the higher corkage fees just to be able to fill an otherwise empty set of tables.
Blind tasting:
They're fun, but my wine experience/knowledge is somewhat limited, so while everyone is trying to figure out the vintage and/or the vineyard where the grapes were grown, I'm simply trying to pick out the varietal. Your group may consist of seasoned professionals, which will usually have a great time with a blind tasting. The one or two newbies to wine, may feel a little less inclined to summize a guess, and therefore remain quiet the entire night. For your first, I suggest a non-blind tasting.
Glassware:
Depending on the size of the group, the restaurant may or may not be able to accomodate your stemware requirements. Figure on a group of ten, the need for a minimum of two to three glasses each. Some of the finer establishments may have an abundance of Riedel glasses to go around, but most will not - especially if you consider that there may be others in the restaurant that also require stemware. Simply ask when making the phone call, and be prepared to bring your own. Actually, alot of people prefer to bring their own anyways. Just make sure the restaurant can supply you with some water pitchers (to be able to top up your water glass for rinsing your palate AND the stemware between wines), as well as a few champagne buckets for the group to be able to dump wine and water into.
WARNING:
Offlines are wayyyyyy fun, and a great way to meet people who share the same interests as you. They're a great way of sharing your stash with people that appreciate it, rather than your neighbor who thinks his father makes the best wine in the world...so-to-speak. And the knowledge you get from those around you is priceless, for as much as YOU know, there's always someone who knows more. Plus, you get to taste numerous wines, some of which you may have had no idea how good they were, or others that you may decided to pass on. Having tasted it, you can decide for yourself whether you were a moron for walking by it at the store, or if you should leave the offline to go get some! Be forewarned, however...offlines are addictive!
Good Luck, have fun, and post your impressions after you've been de-virginized!
Should you need further help, my email is my screen name (no capitals) at yahoo dot ca.
I can really use all the help I can get!
Will keep you posted...